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Discovery of Cells
• 1665 Robert Hooke noticed
thousands of tiny chambers
while looking at cork
• He named these “cells”
because they looked like the
small chambers of his
monastery
• Anton van Leeuwenhoek noticed a
world of tiny organisms were
everywhere, including his water
• Matthias Schleiden concluded
that all plants were made of cells
• Theodore Schwann stated all
animals are made up of cells
• Virchow concluded new cells are
made from existing cells
• All living things are
composed of cells
• Cells are the basic unit of
structure and function in
living things
• New cells come from other
cells
Prokaryotes vs. Eukaryotes
Prokaryotes…
• Do not contain a nucleus
• Are smaller and simpler
• Carry out every activity
associated with living things
• Like bacteria!
Which
one am I
???
Eukaryotes
• Usually larger and more complex
• Highly specialized
• Genetic material is separated
from the rest of the cell in a
nucleus
• Can be a single cell or
multicellular organism
Examples
Eukaryotic cell structure
• Made up of organelles or
“little organs”
• Divided into 2 parts: nucleus
& cytoplasm
• Cytoplasm is outside the
nucleus
CHROMATIN
• DNA bound to protein in the
nucleus
Nucleolus
•Where ribosomes
are made
Ribosomes
• Are made of RNA and protein
• Assemble proteins
• Protein assembly instruction
comes from the nucleus
• Cells active in protein
synthesis have many
ribosomes
Endoplasmic reticulum
• Makes and exports proteins
and lipids
• Rough ER makes proteins
ribosomes!
• Smooth ER
makes enzymes
Golgi Apparatus
Lysosomes
• Clean up crew, remove junk!
• Digest or break down lipids,
carbohydrates, proteins and
old organelles
• Filled with enzymes
• Converts food into
compounds the cell uses
• Mitochondria are from the
egg cell, so thank your MOM!
Chloroplasts
• Plant cells
• Capture energy from the sun
and convert it into chemical
energy… Photosynthesis
Cytoskeleton
• A network of protein
filaments
• Help the cell maintain its
shape/structure
• Made of microtubules and
microfilaments
Centrioles
• Help organize cell division
Cilia & Flagella
7.3 Cell Boundaries
• All cells are surrounded by a thin,
flexible membrane
• Plant cells also have a cell wall
surrounding the membrane
Cell Membrane
• Regulates what comes in
& out of the cell
• Provides structure and
support
• Made of a lipid bilayer
which provides a strong
flexible barrier
A membrane mosaic?
• The lipid bilayer has carbs AND
proteins embedded within!
• Located outside cell membrane
in plant, algae fungi and
prokaryotic cells
• Usually made of carbs & protein
• Plant cell walls made of
cellulose
• Provides protection and support
• When particles move from areas of
high concentration to areas of low
concentration
• Equilibrium occurs when the
concentration of solute (particles)
is the same throughout
The Dye = Solute
Water= Solvent
• Water passes easily
across membranes
• Osmosis is the diffusion
of water across a
selectively permeable
membrane
Isotonic
Facilitated Diffusion
• Certain molecules can
pass through cell
membranes with help from
protein friends
Active Transport
• Sometimes cells must move
materials the opposite direction
as diffusion
• This requires energy
• Transport proteins or “pumps”
help this happen
• A form of endocytosis
• Means “cell eating”
• Cell sends out projections
called pseudopodia
• Means “cell drinking”
• Usually particles are
dissolved in water
• A form of endocytosis